Antiurolithiatic potential of neeri against calcium-oxalate stones by crystallization inhibition, free radicals scavenging, and NRK-52E cell protection from oxalate injury

Background: Neeri is a well-established polyherbal formulation prescribed for renal stones by the physicians but has not been experimentally evaluated for its antiurolithiatic potential using cell-lines. Objective: This study is aimed to scientifically substantiate the antiurolithiatic effect of Neeri extract (NRE) through calcium oxalate (CaOx) crystallization inhibition, scavenging of free radicals, and protection of renal tubular epithelial NRK-52E cells from oxalate-induced injury. Materials and Methods: The crystallization inhibition was studied by turbidimetric assay while the free radical scavenging potential was determined for superoxide and nitric oxide (NO) radicals. The cytoprotective effect against oxalate-induced injury was assessed by estimating lactate dehydrogenase (LDH) leakage and determining cell viability using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: NRE significantly inhibited the CaOx crystallization in a concentration-dependent manner and also scavenged superoxide (IC₅₀ 302.88 μ g/ml) and NO (IC₅₀ 300.45 μ g/ml) free radicals. It did not show any significant cytotoxicity for NRK-52E cells till the highest dose (500 μ g/ml) and found to be safe. When NRK-52E cells, injured by exposing to oxalate crystals for 24 h, were treated with NRE, it appreciably prevented the cell injury in a dose-dependent manner. It significantly decreased the elevated LDH leakage toward normal range and improved renal cell viability (82.37% ± 0.87%), hence, prevented growth and retention of crystals. Conclusion: The experimental findings concluded that Neeri is a potent antiurolithiatic formulation that inhibited CaOx crystallization and prevented tubular retention of crystals by protecting the renal cells against oxalate-induced injury as well as reducing the oxidative stress by scavenging free radicals.